DE370854C - Process for the preparation of sulfur and nitrogen-containing condensation products of the aromatic series - Google Patents

Description

Process for the preparation of sulfur- and nitrogen-containing condensation products of the aromatic series. In the main patent 36o69o and the additional patents 367344 and 367345 it is indicated that the action of excess chlorosulfur (S2 02) on aromatic amines which have an alkyl group in their molecule p-position to the amino group, such as. B. p-toluidine, m-xylidine, deviates from the general type. Under the working conditions chosen there, the reaction does not stop with these bases when the -SS-Cl radical enters the molecule; instead, further substitution of sulfur takes place and the end products formed have the character of yellow sulfur dyes.

It has now been found that the normal amines can also be derived from these amines Sulfur- and nitrogen-containing condensation products of chlorosulfur with only make a -S-S-Cl residue in the molecule if the reaction is careful at the lowest possible temperature and expediently in the presence of a suitable, Carries out a diluent inert to chlorosulfur. In addition to hydrocarbons, Nitro hydrocarbons and glacial acetic acid have particularly been used for these purposes as much as possible Anhydrous formic acid is proven because it slows down the reaction rate causes.

The normal products of the action of sulfur chloride on primary, aromatic amines with a p-alkyl group to the amino group obtained in this way do not have the character of a dye; Their relative stability in aqueous mineral acid solution is remarkable; in acetic acid or neutral aqueous solution, however, they easily form the normal reaction products of the body class with water.

These latter compounds provide the upon treatment with alkalis correspondingo -Aminothiophenols and in the condensation with monochloroacetic acid the corresponding o-aminoarylthioglycolic acids in alkaline solution.

Example i.

5.5 kg of p toluidine are dissolved in approximately 20 kg of nitrobenzene and this solution is allowed to run into 20 kg of chlorosulfur (S. C1,) with cooling. The mixture is first kept at normal temperature, then at 30 to 40 ° C. for several days with stirring, diluted with an inert hydrocarbon such as benzene, crude xylene or ether, the precipitate is filtered off with suction and washed with this diluent to free it from adhering excess chlorosulfur . To clean it, it is then slurried with about 2001 water, to which a few kilograms of hydrochloric acid have expediently been added, and stirred for some time.

The new, normal condensation product of chlorosulfur with p toluidine goes into solution with a yellow color, while the higher sulfurized products remain unsolved. Picric acid can be added from the filtered solution precipitate the compound as a yellow-orange, sparingly soluble picrate.

The hydrochloric acid solution is blunted with acetate or with alkalis Neutralized to a weakly acidic reaction, it separates after standing for a long time the reaction product with water in the form of colorless crystal flakes. It will Reaction product condensed in alkaline solution with monochloroacetic acid, see above the o-thioglycolic acid of p-toluidine and its internal anhydride are formed smoothly 15 2 `C melts. Example 2. 7.2 kg of hydrochloric acid p-toluidine are added to a mixture of 161, g of glacial acetic acid and 2q. kg of sulfur chloride entered and several days first stirred at ordinary temperature, then at 30 to 40 ° C. You then pour that Reaction mixture in about Zoo 1 ice water, stir for some time until complete Decomposition of the excess chlorosulfur and filtered. The new condensation product is contained in the yellow colored solution and can be made from the same as in the example i is specified to be deposited. The filtrate can also be made alkaline and remove unaffected p-toluidine with steam. From the cooled solution The new compound crystallizes in the form of the o-disulfide in colorless flakes the end. Example 3.

12 kg of m-xylidine are introduced into 12 to 15 kg of formic acid which is as anhydrous as possible, with cooling, and this mixture is then added to 50 kg of chlorosulfur in a suitable stirred vessel; Temperature increases above 30 ° C should be avoided as much as possible. The mixture is initially stirred for 1 to 2 days at normal temperature, then for about the same time at 30 to 40 ° C. and, when the reaction is complete, it is poured into about 300 liters of ice water. The new condensation product goes into solution with a yellow-brown color, while small amounts of higher sulfur products and sulfur remain undissolved. It is filtered, the picrate of the new compound can be precipitated from the filtrate by means of picric acid as an orange-colored, sparingly soluble crystalline powder or, after the mineral acid has been blunted with alkalis or acetate, the poorly soluble water reaction product can be separated off in the form of colorless crystal flakes. From the latter one obtains according to the procedure of the patent 36q.822, K1. 12q, slightly the o-thioglycolic acid of m-xylidine, the internal anhydride of which melts at about 160 ° C.

p toluidine gives the in the same process in good yield Examples i and 2 described compounds.

Instead of a solution or mixture of the formic acid salts of the bases The dry formic acid salts of the bases can also be used in or with formic acid entered in excess chlorosulfur and otherwise, as described above, to be worked.

Claims (2)

PATENT CLAIMS: i. Modification of that protected by patent 36o6go Process for the preparation of sulfur- and nitrogen-containing condensation products of the aromatic series, consisting in that one for the purpose of obtaining compounds without coloring character from such aromatic amines, which in their molecule contain an alkyl group in the p-position, chlorosulfur (S. C1) in excess these bases or their salts at lower, expediently not exceeding 50 ° C Let the temperature act. 2. Embodiment of the method according to claim i, characterized characterized in that the condensation in the presence of an anhydrous, against Solvents or diluents that are inert to chlorosulfur, in particular of nitro hydrocarbons, Glacial acetic acid or anhydrous formic acid, if possible.